This disclosure relates to near field communication (NFC), and more particularly, to an NFC circuit including an NFC reader circuit and an NFC card circuit and a method for operating the same.
Near field communication (NFC) is a type of radio frequency identification (RFID) technology and a contactless communication technology that generally uses a 13.56 MHz frequency bandwidth. NFC applications are often low cost, and may have short communication distance, thereby having relatively high security.
Existing NFC circuits include an NFC reader circuit and an NFC card circuit. The NFC reader circuit is an NFC reader for communicating with the outside, and the NFC card circuit is an NFC card (or tag) for communicating with outside. When an NFC circuit operates as the NFC reader, for example, the NFC reader circuit is enabled and the NFC card circuit is disabled, a leakage current output from the NFC reader circuit may be applied to the NFC card circuit. The leakage current may damage the NFC card circuit.
Also, a resonant frequency when transmitting data and a resonant frequency when receiving data are generally the same in the typical NFC circuit. As a result, if a coupling factor with the outside, for example, with the other NFC circuit is large, the impedance of an antenna is reduced, thereby reducing communication efficiency.